Photoacoustic imaging is a hybrid biomedical imaging modality developed based on a photoacoustic effect. The photoacoustic effect is a formation of sound waves following light absorption in a sample. In photoacoustic imaging, non-ionizing laser pulses are delivered into biological tissues. Some of the delivered energy is absorbed and converted into heat, leading to transient thermoelastic expansion and thus wideband (e.g. MHz) ultrasonic emission. Generated ultrasonic waves are then measured by ultrasonic detectors to form images. Two dimensional (2D) or three dimensional (3D) images of targeted areas can then be formed.
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